Skeletal System

skeletal system

organ system with tissues that grow and change throughout life

skeletal system

composed of bone, cartilage, ligaments

cartilage

embryonic forerunner of most bones and covers many joint surfaces

ligaments

hold bone to bone at joint

function of skeleton

provides support

function of skeleton

allows for movement

function of skeleton

protection of delicate organs

function of skeleton

blood formation in marrow or hemopoiesis

function of skeleton

electrolyte balance - calcium and phosphate

function of skeleton

acid-base balance

function of skeleton

detoxification

cartilage

semirigid connective tissue

cartilage

weaker than bone

flexible and resilient

mature cartilage

avascular - has no blood supply

chondroblasts

cell of cartilage

produce matrix

chondrocytes

cell of cartilage

surrounded by matrix

occupy small spaces called lacunae

function of cartilage

supporting soft tissue

function of cartilage

gliding surface at articulations

* smooth surfaces where bones meet

function of cartilage

precursor for bone growth

* beginning in embryo, then replaced by bone

bone

complex organs containing all four tissue types

* primarily bone connective tissue
* extracellular matrix is sturdy and rigid due to decomposition of minerals

function of bone

support and protection of more delicate organs

function of bone

movement - attachment site for muscles

function of bone

hemopoiesis - blood cell production in red bone marrow

function of bone

storage of mineral and energy reserves

* calcium and phosphate
* lipids stored in yellow marrow

axial skeleton

central supporting axis of body

includes skull, vertebral column, thoracic cage

appendicular skeleton

upper limbs and pectoral girdle

lower limbs and pelvic girdle

long bone

greater length than width

short bone

nearly equal length and width

flat bone

thin surface

irregular bone

complex shape

sesamoid bone

floating bone

number of bones at birth

270

number of bones as adult

206

number of bones in axial skeleton

80

number of bones in appendicular skeleton

126

diaphysis

shaft of long bone

epiphysis

knobby end of long bone

strengthens joints

attachment site for tendons and ligaments

metaphysis

region between diaphysis and epiphysis

contains epiphyseal (growth) plate

articular cartilage

thin layer of hyaline cartilage covering the epiphysis

reduces friction and absorbs shock in moveable joints

blood vessel

well vascularized

medullary cavity

hollow cavity filled with yellow marrow

membranes in long bones

periosteum, perforating fibers (Sharpey’s), endosteum

epiphysis

where spongy bone and red marrow is

diaphysis

where yellow marrow is

endosteum

covers most internal surfaces of bones

contains osteoprogenitor cells, osteoblasts, osteoclasts

osteoblast

lay doen calcium

osteoclasts

active in remodeling, growth, fracture repair

respond to chemical stimuli

periosteum

covers external surfaces of bone - except where articular cartilage does

dense irregular connective tissue

attached by perforating fibers embedded in the bone matrix

acts as anchor for blood vessels and nerves

contains osteoprogenitor cells and osteoblasts

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structure of short bone

generally cube-shaped

structure of short bone

proportionally large articular surface in order to articulate with more than one bone

structure of flat bone

thin, flat, curved

structure of irregular bone

irregular shape, “misfits”

structure of sesamoid bone

small bones embedded with another structure

structure of sesamoid bone

floating

compact bone

solid and relatively dense

compact bone

external surfaces of long and flat bone

spongy bone

open lattice of narrow plates called trabeculae

spongy bone

porous appearance

* spaces filled with bone marrow

spongy bone

lightweight but strong

spongy bone

internal surface of bone

bone marrow

soft tissue located in medullary cavities of long bones, spaces within spongy bone, and large central canals within osteons

types of bone marrow

red marrow

yellow marrow

red marrow

hemopoietic tissue (blood forming tissue)

both red and white blood cells are made here

yellow marrow

mainly fat

lots of calories

red marrow location

skull

vertebrae

sternum

ribs parts of pelvic girdle

proximal heads of humerus and femur

yellow marrow location

long bones of limbs

ossification

osteogenesis

bone formation

begins with mesenchyme

methods of ossification

intramembranous

endochondral

intramembranous

provides flat bones of skull and most of clavicle

develops from mesenchyme

endochondral

most bones develop this way

bone develops from hyaline cartilage model

bone elongation

bones grow longer at epiphyseal plates

plates are made of hyaline cartilage

interstitial growth

also known as longitudinal

long bones growth in length

occurs in epiphyseal plate

appositional growth

growth in a bones diameter

occurs in the periosteum

bone growth

growth, maintenance, repair depend on hormones, vitamins, exercise

tuberosity

large bump

process

projection

tubercle

small bump

spine/spinous process

long, thin projection

condyle

bony knobs at the end of long bones

large, smooth, rounded oval structure

epicondyles

small knobs on condyles

fossa

flattened or smooth hollow surface

facet

small smooth shallow surface

notch

cut out area

foramen

hole

head

prominent, rounded epiphysis

trochlea

smooth, grooved, pulley-like process

alveolus

deep pit or socket in the maxillae or mandible

sulcus

narrow groove

crest

narrow prominent, ridgelike projection

line

low ridge

ramus

angular extension of a bone relative to the rest of the structure

trochanter

massive, rough projection found only on the femur

canal

passageway through a bone

fissure

narrow, slitlike opening through a bone

meatus

passageway through a bone

sinus

cavity or hollow space in a bone

joints

primary function is to provide stability

joint types

synarthrodial (fibrous)

amphiarthodial (cartilagenous)

diathrodial (synovial)

synarthrodial joint

immovable joint

attenuates force with no movement

amphiarthrodial joint

minimal motion

no bone to contact (cartilage or intermediate structure between)